Study on non-point source pollution characteristics under different spatial scales: a case study of Hanjiang River Basin, China.

In recent years, the research on non-point source (NPS) pollution has been deepening, but it is focused on the large-scale watershed or region. There are a few studies on the scales of small watershed and runoff plot, and it is even less to analyze the characteristics and mechanism of non-point source pollution in certain watershed by combining three different scales. Based on the combination of natural rainfall monitoring and MIKE model simulation, the Shaanxi section of Hanjiang River Basin in China was taken as an example to study the characteristics of NPS pollution at different spatial scales. The results showed that there was an obvious correlation between rainfall and runoff/sediment yield. The order of runoff yield/sediment yield per unit area was as follows: woodland > forested and grassy land > arable land. There was a significant relationship between the loss of total phosphorus and the sediment yield in the runoff plots. The total nitrogen pollution was serious, with an average concentration of 3.8 mg/L. The nutrient loss was in the form of nitrate nitrogen, with an average proportion of 63.06%. For small watershed scale, the characteristics of rainfall runoff pollution generation were like runoff plot scale, both have obvious initial scour phenomenon. However, compared with runoff plot scale, the pollutant loss concentration increases with a strong lag. The MIKE model based on the coupling of hydrology, hydrodynamics, and pollution load had a strong applicability in the basin. The critical source areas of NPS pollution were identified, and five scenarios were laid out in the areas for the control of NPS pollution. Centralized livestock and poultry farming had the best reduction effect.

Intermittent pressure imitating rolling manipulation ameliorates injury in skeletal muscle cells through oxidative stress and lipid metabolism signalling pathways.

BACKGROUND: Traditional Chinese medicine manipulation (TCMM) is often used to treat human skeletal muscle injury, but its mechanism remains unclear due to difficulty standardizing and quantifying manipulation parameters. METHODS: Here, dexamethasone sodium phosphate (DSP) was utilized to induce human skeletal muscle cell (HSkMC) impairments. Cells in a three-dimensional environment were divided into the control normal group (CNG), control injured group (CIG) and rolling manipulation group (RMG). The RMG was exposed to intermittent pressure imitating rolling manipulation (IPIRM) of TCMM via the FX­5000™ compression system. Skeletal muscle damage was assessed via the cell proliferation rate, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content and creatine kinase (CK) activity. Isobaric tagging for relative and absolute protein quantification (iTRAQ) and bioinformatic analysis were used to evaluate differentially expressed proteins (DEPs). RESULTS: Higher-pressure IPIRM ameliorated the skeletal muscle cell injury induced by 1.2 mM DSP. Thirteen common DEPs after IPIRM were selected. Key biological processes, molecular functions, cellular components, and pathways were identified as mechanisms underlying the protective effect of TCMM against skeletal muscle damage. Some processes (response to oxidative stress, response to wounding, response to stress and lipid metabolism signalling pathways) were related to skeletal muscle cell injury. Western blotting for 4 DEPs confirmed the reliability of iTRAQ. CONCLUSIONS: Higher-pressure IPIRM downregulated the CD36, Hsp27 and FABP4 proteins in oxidative stress and lipid metabolism pathways, alleviating excessive oxidative stress and lipid metabolism disorder in injured HSkMCs. The techniques used in this study might provide novel insights into the mechanism of TCMM.

Trade-off between allocation to reproductive ramets and rhizome buds in Carex brevicuspis populations along a small-scale elevational gradient.

The trade-off between allocation to sexual and clonal reproduction in clonal plants is influenced by a variety of environmental factors; however, it has rarely been examined under field conditions. In this study, we investigated the trade-off between two modes of reproduction in Carex brevicuspis C. B. Clarke across a small-scale elevational gradient (21-27 m a.s.l.) at the Dongting Lake wetlands, China. The proportion of biomass allocated to and the density of reproductive ramets were higher at low than at intermediate and high elevations. In contrast, the proportion of biomass allocated to and the density of rhizome buds were lower at low than at intermediate and high elevations. Redundancy analysis showed that sexual reproduction was positively correlated with soil moisture content, soil organic matter, total phosphorus, and pH, and negatively correlated with elevation and ramet density. Our findings suggested that allocation to sexual reproduction is favored in disturbed habitats with fertile soils, whereas allocation to vegetative propagation is favored in stable and competitive habitats. Trade-off between allocation to sexual reproduction and vegetative propagation along an elevational gradient might be a reproductive strategy of C. brevicuspis to adapt to the water level fluctuations in wetland habitats.

Optimization of ultrasound extraction of Alisma orientalis polysaccharides by response surface methodology and their antioxidant activities.

Rhizoma alismatis (the rhizome of Alisma orientalis) polysaccharides (RAP) have been reported to have a variety of important biological activities. However, effective extraction of RAP has been an unsolved issue. In this study, we used an ultrasound method for high yield extraction of RAP and optimized the conditions using the response surface methodology (RSM). Following multiple regression analyses of the experimental results, we applied the 3-D response surface and the contour plots to determine the optimal conditions, which were found to be ultrasound treatment at 76.1°C for 75.2 min, and water to material ratio at 30.1 ml/g. Under such conditions, the yield was 6.90% which was much higher than traditional hot water extraction yield (3.41%). The fractionated RAPs following stepwise ethanol precipitation showed strong antioxidant activities. The results indicated that ultrasound extraction was a very effective method for the extraction of RAP and the polysaccharides could be explored as a potential antioxidant agent for use in medicine or functional food.